Digital Zone System ~ Sony A5000 in-camera Black and White jpg generation

Moving from silver halide film to digital over fifteen years ago I'm surprised how long it's taken me to sort out a Digital Zone System.  I'd used the Zone System for everything I shot on film and was very used to the process and how it guided results.

For whatever reason I made a long series of assumptions about how digital behaved and what manufacturers provided.  I'd turned over my thinking and reasoning to others and feel now that I missed an opportunity to successfully transition from the old Adams/White Film Zone System to a Digital Zone System. 

Using digital image processing tools, mousing over an image and using "curves" can show rather precisely where on the curve various parts of the moused over scene are.  

I knew this from Day One many years ago.  Yet I didn't realize nor understand how useful this actually is.  I must be slow and that's all there is to it.  Now that I'm "here" I can move forward using knowledge and accuracy, even as I'm still shaking my head at my ignorance.  

Zone separation by 1 f-stop/1EV applies just as well to digital as it does on film, and with better accuracy, too.

Turning my attention to a Sony A5000...  it comes with a Bionz X ASIC that offers additional features over the Bionz ASIC used in, for example, the Sony NEX-5T.  I was interested to see if there were any obvious changes/updates to how the newer ASIC treated Creative Style Black and White in-camera processing. 

Sony A5000 ~

Varying Creative Style Black and White Contrast as well as Dynamic Range Optimization (DRO), here's what I see.  The upper Step Wedge is the synthesized reference.

 

 

As with the Sony NEX-5T Bionz ASIC, the A5000 Bionz X ASIC shows that -

• Contrast changes highlights as well as shadows (as expected)
• DRO raises the dark tones up to Zone 5 to varying degrees depending on DRO "strength" ~ the effect is to "open the shadows" to varying degrees while still doing _nothing_ to the highlights

In the wild: Here's the recipe I've come to like when out and about photographing in old traditional 6:1 contrast ratio scenes:

• Creative Style Black and White Contrast == 0 
• DRO == 1  

-------------- References From Prior Posts ---------------

Zone System Definition ~

• Zones are separated by 1 f-stop/1 Exposure Value (EV)
• Zone 5 ~
• old film days == 18% gray
• digital tone value == #76(hexidecimal)/118(decimal)
• Pure Black
• old film days == Zone 0 at -5EV
• digital tone values == -EV-whatever the camera system can deliver (commonly different between RAW - ideally -10EV!!!  and the in-camera jpg generator - Sony Creative Style Black and White in-camera seems set at -5EV)
• Pure White
• old film days == Zone 10 (last definition) or Zone 9 (earlier definition)
• digital tone value == +4EV  as Zone 9 for the Sony cameras I own (this has been measured and is very important! to successfully using the Zone System in digital)

Digital Zone System In-Camera jpg Step Wedge generation ~ 

To evaluate in-camera jpg generation here's the method I used to create a Step Wedge that I could visually inspect to when making various in-camera parameter changes -

•  Sony camera settings - 
• ISO == 100
• Creative Style B&W
• B&W Contrast to a test value - I've tried -3 to +1
• Dynamic Range Optimization - Off or DROx where x == [1, 2, 3]
• Meter to Spot
• Output file == jpg 
• Manual focus and defocus the lens as much as possible to fully blur the scene (wanting just tone, no texture) 

• Using an evenly lit surface (piece of paper, wall, etc)...
• Take two photos at 0EV and verify which 0EV setting gives exactly #76/118(dec) in the center (where the Spot meter metered) by measuring the tonal value using an image processing software on a computer.  This will be Zone 5 per definition.
  NOTE: Sony seems to offer two 0EV settings that are 0.3EV separated on their APS-C cameras.  I've found the system tells me when 0EV is reached, but then if I go 0.3EV further, the meter STILL reads 0EV.  Often the lower 0EV indicated is the one that matches the Zone 5 specification.  Then I use that value as the starting point and increase/decrease exposures using that as the reference/starting point.  Using the lighter 0EV value over-exposes by 0.3EV (as expected) even though it readss 0EV on the display.  In practice, some of my Sony cameras matrix meter for lower 0EV, while others meter for the upper 0EV.  I find this strange but it might fit in with whatever industry standards there are for metering (ie: +/- lee-way, or somesuch).  I've not (yet?) seen this on full frame Sony.
• Raise EV by 1EV
• Take a photo
• Measure and note as Zone 6 the tonal value as read on a computer 
• Raise EV by 1EV
• Take a photo
• Measure and note as Zone 7 the tonal value as read on a computer 
•  Raise EV by 1EV
• Take a photo
• Measure and note as Zone 8 the tonal value as read on a computer 
• Raise EV by 1EV
• Take a photo
• Measure and note as Zone 9 the tonal value as read on a computer
• Verify that this tonal value is exactly or very very nearly Pure White
•  Returning to Zone 5/0EV... lower the EV by 1EV
• Take a photo
• Measure and note as Zone 4 the tonal value on a computer 
•  Lower the EV by 1EV
• Take a photo
• Measure and note as Zone 3 the tonal value on a computer 
• Lower the EV by 1EV
• Take a photo
• Measure and note as Zone 3 the tonal value on a computer 
• Lower the EV by 1EV
• Take a photo
• Measure and note as Zone 2 the tonal value on a computer
• Lower the EV by 1EV
• Take a photo
• Measure and note as Zone 1 the tonal value on a computer
• Lower the EV by 1EV
• Take a photo
• Measure and note as Zone 0 the tonal value on a computer - this should record as #00/00(decimal), Pure Black

In practice, older/early Sony mirrorless cameras only provide +/-3EV on the exposure wheel.  In these cases I use "M" (Manual) mode, set the aperture and ISO, then vary the shutter speed by 1EV up/down the test range.  On more recent cameras where +/-5EV is available on the I set the system to "S" (Shutter) mode, set the ISO, then vary the EV by 1EV using the exposure wheel.  Why Sony allows +5EV is beyond me, but that's a topic for another time (noting that +5EV is 1EV ABOVE completely and utterly saturated pure white). 

Default Creative Style Black and White as Dreck! ~

 

Note how the Creative Style Black and White curve in red
takes a dive below Zone 5/0EV.  This is what I think the
"cool kids" would call "crushing the blacks."  I find the
effect to be absolute dreck.  It should be noted that 
this was a creative decision taken by Sony some time 
back and there must've been valid reasons for doing
things this way. 

Notes On USE: In a practical sense I find Zones 3 through 7 to be the most important.  If those are as close to 1EV separated as possible, then I like the output.  This is very similar to what I experienced back in the film days.

For the shadow areas I find I prefer Zones 0 through 2 to be rather outside the 1EV separation definition.  This matches film curves more closely and since I'm used to that I like a certain combination of Contrast and DRO settings.

For the highlights I like to make them "sparkle" if I can.  I find I prefer Zone 8 to be pushing closer to Pure White than not.  Having just written that, however, I shot an entire series of in-camera generated images that pleased me using nothing but Contrast == -3.  So it's worth testing different combinations of Contrast and DRO to see what works best for oneself.